Telephony.



v E. R. OORWIN.

TELEPHONY.

nrnronron Hun un. n4, 1011.

Patented Aug. 26, 1913.

9 lKEBTI-IHEET 1.

E. R. CORWIN.

TELEPHONY. ArPLxoATIoN FILED APB. 24, 1911.

1,071,21 1, Patented Aug. 26, 1913.

2 SHEETS-BHEET 2.

SWITCH SE l. E c ro R VERTICAL MAGNET ausm' asians 1n: lemmi! 4* Millal o Q RELEAS MAGNET OR MRL TCM sarmas` PATENT Voni-non ELMER E. GORWIN, OF CHICAGO, ILLINOIS, ASSIG'NOB, TO CORWIN TELEPHONE MANU- FACTURING COMPANY, A CORPORATION 0F ILLINOIS.

TELEPHONY.

Specification of Letters atent.v

Patented Aug. 26,1913.

Application filed Alpril 24, 1911.' Serial No. 622,944.`

citizen of the United States, residing at' Chicago, in the county of Cook and State of Illinois, have' invented a certain' new and useful Improvement 'in Telephony, of which the following is av full, clear, "concise, and'exact description, reference being'had to the accompanying dra-wings, forming a partei this specification.'

My invention relatesi to telephonyA and particularly' to that class of telephony em-- ploying two or more telephonelines; a third telephone line; means' whereby `either of theirst 'telephone lines may become 'connected with thethird'telephone line; means for automaticallylett'ecting an'eXtension of the third telephone line, as, for example', I'wouldr be the caseii such third telephone line were a trunk line extending from the stations o1 the first telephone lines to an automatic or semiautomatic exchange.'

My invention; in itspre'ferred embodiment includesva numberof trunklines thus extending 'tromv an automatic or semi-automatic exchange .to fthe stations of a pluralityot telephonel lines.

The Einvention has characteristics' which will better be understood by a description of one embodiment of the invention,l to which 'l do notlimit myself however, the

accompanying 'drawings illustrating the embodimentbf the 'invention that has been selected for the'purpose'ot disclosing the invention. K

Figure 1 of the drawings shows an intercommunicating telephone system illustrated.V Fig'. 2 illustrates-one type of automatically operated selecting mechanism for automatically 'effecting extensions 'of the trunk lines at the exchange .to which the trunk lines'lead, the particulary type of equipment shown in Fig. 2 being that with which thoseskilled in the art a'ie very familiar and which is employed for automatically` connecting vcalled subscribers lines with `the lines ot calling parties.

ln describing the' invention illustrated l will omit detailed reference to the means and mannerv employed by parties at the two intercommunicating stations No. 1 and No. 2 for bringing about telephonie connections between said Stations, since all of the apparatus shown below the telephonie equipment at station No. 1 and No.- 2 is .well known by 'those skilled in the-art.

A trunk line 3 and a trunk line 4 is illustrated as extending from the auto-matic telephone `exchange to each of the stations `of the yintercommunicating system.. There isprovided at each of the intercommunieating stations a plurality of selecting keys v11,l one individual to each trunk line and each adap'ted'for cooperation with a pin 12 mounted upon a connecting bar '13, whereby each keyy upon being fully depressed will release its companion so that one key will always occupy a normal position,the llower keys 11 being shown in normalpositions.` The control that each stationhas over the trunk line is similar to that possessed by the other and l will'thereforedescribe in detail the association of but one of the intercommunicating stations with the trunk lines With the understanding that such description would apply to each of the.

so as to establish connection with trunk line' 3 or -for some other reason. The party at station No. 1, in order to accomplish these objects, will fully depress the selecting key 11 individual to trunk line 4 after having removed his telephone Jfrom its switch hook. As a consequence of this operation circuit through the battery 9 at the automatic exchange is closed by way of the sides of the trunk line and a bridge across the sides of the trunk line that is established at station No. 1 and which bridge may be. traced from the upper sido of the trunk line, the two uppermost cout-acts of the selecting key 11, the middle armaturev switch of relay 15 and its alternate contact, the switch hook at station No. 1 and its alternate contact.v the telephone receiver and transmitter at this station, the interrupter a-that 'is employed when the selected trunk line is to be automatically extended, the right hand armature switch of relay 15 and its alternate contact,

the switch contacts 111 of the selecting key 11 to the other side of the trunk line. The manner in which the relay 15 is energized at this stage of the operation is known to those skilled in the practical art and may be described as resulting from a circuit traceable from the upper'pole of battery 16, thc two uppermost contacts of the switch hook at station No. 1, the resting left hand armature switch of relay 17 and its Contact, the winding of relay 15, the engaged contacts 18, to the lower terminal of the battery 16, the contacts 18 being engaged owing to the full depression of the actuated selecting key or switch 11 individual to the trunk line 4. A locking circuit is then established for the relay 15 which may be traced from the upper terminal of the battery 16 through the upper contacts of the switch hook at station No. 1, the left hand armature switch of relay 17, the winding of relay 15, the left hand armature switch of relay 15 and its lowermost contact to the lower pole of the battery 16. As a result, automatic mechanism at-l the exchange may be operated for extending the trunk lines as a consequence of the circuit interruptions effected by the calling party in manipulating the circuit breaking or dial mechanism a.

If the party at station No. 1 should desire to disconnect his telephone from and at the same time hold the trunk line 4 after having secured connection with another party by way of the exchange or after the exchange subscriber has secured connection with station No. 1 by way of the trunk line, then the party at station No. 1 will depress a holding key 22 to bring the normally disassociated relay 23 into association with the trunk line that is to be held, each key 22 at each station being adapted when operated to bring about the association of the relay 23 with the trunk line to which such key is individual and to remove such relay from association with a trunk line with which it was previously, associated owing to the mechanical inter-relation between the keys 22 that enables each key to restore each other key 22 to normal position. A releasing key 24 serves to release any key 22 at its station so that the relay 23 will have no operative association. Under the assumption that the trunk line 4 is to be retained by the party at station No. 1, the key 22 individual to the trunk line is placed in the position indicated, whereby a partial circuit is established for the relay 23, this circuit completed when the button 25 is actuated, each switch 22 being 'associated with a button or switch 25, there being one such switch 25 for each trunk line. The circuit for the relay 23 that is established by the coperation of the switches 22 and 25 may be traced from theV upper pole of the battery 9, through the upper side of the trunk line 4, the contacts of the now actuated key 25, the contacts 26 of key 22, the winding of relay 23, the contacts 27 of key 22, the lower side of the trunk line 4, to the lower pole of the battery 9. The relay 23 thereupon establishes a locking circuit through itself and it will be sufficient to trace a bridge connection between the sides of the trlmk line through the winding of the relay 23, and which bridge connection is traced from the upper side of the trunk line 4, through the contacts 28, the right hand armature switch of relay 23 and its then engaged contact, the windin' of relay 23, the contacts 27, to the lower side of the trunk line. There is thus established a bridge across the trunk line in place of thebridge hitherto traced through the telephone equipment at station No. 1 so that the breaking of the bridge that includes the telephone at station No. 1, and which breaking occurred by the depression of the key 25, is not followed by an operation of the automatic mechanism at the exchange which would disconnect the trunk line from the line automatically connected with it. It is understood that when the key 25 is depressed the telephone equipment at station No. 1 is disconnected'rom the trunk line 4 because of the consequent release of the button 11, which release is followed by the breaking of the bridge including the telephone at station No. 1 and which breaking occurs at the key 11. The party at station No. 1 ic now at liberty to hold conversation with another intercommunicating party, or any other party without the danger of having his conversation transmitted over the trunk line.

When the party at station No. 1 desires to resume connection with the party connected with trunk line et he presses the button l] at his station which is individual to the trunk line 4 so as to reestablish the telephone bridge between the sides of the trunk line at his station and which telephone bridge was previously traced. This telephone bridge is of low resistance compared with the resistance of the relay 23 so 'that the relay 23 is deenergized to break the bridge that said relay previously held across the trunk line wherebythe apparatus at station No. 1 is again placed in control of the automatic mechanism at the exchange to enable the trunk line to be automatically disconnected at the exchange from its extension when the telephone at station No. 1 is restored upon its switch hook, the only bridge then existing at stationNo. 1 being broken to occasion this result in a manner well known by those familiar with the art of automatic telephone exchange practice.

I will now more particularly describe the means. which constitutes an important feature of my invention, whereby thel relay 23 at each intercommunicating station may be used for the purpose which has been described in connection with any of the trunk lines so that it will not be necessary to provide alrel'ay 23 individual to each trunk line at each station. When the relay 23 is unassociated with any trunk line its terminals are free of connection. Each of the terminals of the relay 23 is multiplied, the upper keys 22 and 25 of trunk line 4 will associatev the relay 23 with the trunk line 4 and it will be obvious that a similar depression of the key 22 associated with the trunk line 3 willv bring about a similar association ofthe relay 23 with the trunk line 3 when the key 25 individual to the trunk line 3 is operated after the associatetkey 22 is operated, the key 25 individual to the trunk line 3 having an association with said trunk line similar to the association ot the other key 25 individual to the trunk line 4. The circuit which was previously ltraced as a result of the operation of the keys 22 and 25 ind-ividual to trunk line 4 finds its counterpart in the circuit which results from the depression of the keys 22 and 25 individual to trunk line 3.

I will now describe the circuits and apparatus by whichv an appropriated trunk line is rendered busy sol that another intercommunicating party seeking connection therewith will know ci? its busy condition and how thevtelephone apparatus of an intercommunicating party seekingconnection with an appropriated trunk line is prevented from having telephonie connection with such trunk line. v

Let it be assumed that the party at station No. 2 desires connection with the trunk line 4 at any time after it has been appropriated and whether or not it is held by the apparatus at the intercommunicating station connected therewith. rlthe party at the seeking station, station No. 2, first removes his telephone from its switch hook whereby a circuit is establishedwhich may be traced from the upper pole of the battery 16 through the uppermost contacts of the switch hook at station No. 2, the winding of `the relay 17 the right hand armature switch ot' this relay and its normal contact which is a follow up contact, the contacts 29 and 30,

the' contacts 31 of the now fully depressed key 11 individual to the trunk line 4 at fstation No. 2, the lower side of the trunlrlinell, the contacts 31 of the key 11 at station No. 1: (it now being assumed that telephone station No. 1 is in telephonie connection with 'the trunk line 4) the normally positioned contacts 32 at station No. 1, the left hand armature switch of relay 15 and the middle one of its contacts, to the lower side of the battery 16. At this point it will be explained 'that an alternate circuit connection is established from the contacts 31 at station No. 2 in the event of the key 11 occupying its normal position and of the relay 23 retaining a holding bridge across the trunk line 4 in order that the telephone apparatus at station No. 1 may be disconnected `from said trunk-,line without allowing said trunk line to be appropriated by a seeking station. This alternate circuit is similar to the circuit similarly traced up to and including the contacts 31 at station No. 2, the circuit then continuing from these contacts 31 to the then engaged contacts 33, the two uppermost contacts ofthe then actuated key 22, the left hand armature switch of relay 23 to the lower pole of the battery 16. `With either circuit the right hand armature switch of the relay 17 at station No. 2 makes connection with its alternate contact. before it breaks connection with its normal contact, whereby a locking circuit is established for the relay 17 at station No. 2 which may be traced from the upper terminal of the battery 16 through the uppermost contacts of the switchhook at station No. 2, the winding of the relay 17 and its alternate contact to the lower pole of said battery. The magnet 17 after having been energized establishes a busy test circuit which may be traced from the upper pole of the battery 16 through the circuit interrupting apparatus 34, the middle armature switch of relay 17, its then engaged contact, the switch hook at station No. 2, the receiver and transmitter at station No. 2',`the dial mechanism a at station telephone line leading to station No. 2.

As the relay 15 at station No. 2- has to be energized in order to include the telephone at said station in bridge of the line leading `fto station No. 2, and as the circuit ot thls relay depends upon the engagement of the left hand armature switch 4of relay 17 with its contact, the telephone outfit at station No. 2 is excluded from circuit owing to the fact that the relay 17 at station No. 2 was energized as a consequence of the circuitconnections resulting from the operation of the key 11 at station No. 2 individual to line 4 and which circuit connections were with after -the trunk lines have been taken for ilse.

In my applications Serial Nos. 622,936 and 622,942 filed April 24, 1911 I have broadly claimed the use of supplemental means for preventing that operation of selecting mechanism that would cause the removal of telephone line extensions which had become connected with telephone lines by the selecting mechanism.

While I have herein shown and particularly described one type of equipment carrying out my invention, I do not wish to be limited thereto as changes may readily be made without departing from the spirit of my invention, butl Having thus described my invention, I claim as new and desire to secure by Letters Patent the following:

1. A telephone exchange system including a plurality of telephone lines; a telephone exchange; a plurality of trunk lines intervening between said telephone exchange and the telephone stations of the aforesaid lines; selecting mechanism at the exchange for automatically connecting extensions with said trunk lines; and means interchangeably associated with the trunk lines for preventing the selecting mechanism from separating a trunk line and the extension connected ltherewith bythe selecting mechanism.

2. A telephone exchange system including a plurality of telephone lines; a telephone exchange; a plurality of trunk 'lines`inter-' vening between said telephone exchange and the telephone stations of the aforesaid lines; selecting mechanism at the exchange for automatically connecting extensions with said trunk lines; and electro-magnetic means interchangeably associated with the trunk lines for preventing the selecting mechanism from separating a trunk line andthe extension connected therewith by the selecting mechamsm. f

3. A telephone exchange 'system including a plurality of telephone lines; a telephone exchange; a plurality of trunk lines intervening between said telephone exchange and the telephone stations of the aforesaid lines; selecting mechanism at the exchange fo-r automatically connecting extensions with said trunk lines; means interchangeably associated with the trunk lines for preventing the selecting mechanism from separating a trunk line and the extension connected therewith by the selecting mechanism; and means for preventing other telephone stations from efectmg operative connect-ion with a trunk line wit-h which the aforesaid means has become operatively associated.

4. A telephone exchange system including a plurality ofgtelephone lines; a telephone exchange; a plurality of trunk lines intervening between said telephone exchange and the telephone stations of the aforesaid lines; selecting mechanism at the exchange for automatically connectingextensions with said trunk lines; electro-magnetic means interchangeably associated with the trunk lines for preventing the selecting mechanism from separating a trunk line and the extension connected therewith by the selecting mechanism; and means for prevent-ing other telephone stations from effecting operative connection with a trunk line with which the aforesaid means has become operatively associated.

`5. A telephone system including two or more telephone lines each extending from its own station to the station of the other line, there being means governed at the telephone stations whereby telephonic connection' may be effected between the stations;

a telephone exchange; a plurality of trunk lines intervening between said telephone exchange and the telephone stations of the aforesaid lines; selecting;v mechanism at the exchange for automatically connecting extensions with said-trunk lines; and means interchangeably associated with the trunk lines for preventing the selecting mechanism from separating a trunk line and the extension connected therewith by the selecting mechanism.

6. A telephone system including two or more telephone lines each extending fromits own station to the station of the other line, tlV re being means governed at the telephone stations whereby telephonie lconnection may be effected between the stations; a telephone exchange; a plurality of trunk lines intervening between said telephone exchange and the telephone stations of the aforesaid lines; selecting mechanism at the exchange for automatically connecting extensions with said trunk lines; and electro-magnetic means interchangeably associated With the trunk lines for preventing the selecting mechanism from separating a trunk line and the extension connected therewith by the selecting mechanism.

7. A telephone exchange system including a plurality of telephone lines; a telephone exchange; a trunk line leading to said telephone exchange from'the stations of said telephone lines; selecting mechanism at the exchange for automatically connecting ex-.

tensions with said trunk lines; means whereby either of the telephone lines may becomel connected witlz the trunk lines; means at the ing means of the other station or stations seeking the trunk line.

8. A telephone exchange system including a plurality of telephone lines; a telephone exchange; a trank line leading to said telephone exchange from the stations of said telephone lines; selecting mechanism at the exchange for automatically connecting extensions with said trunk lines; means whereby either ot the telephone lines may become connected with the trunk line; circuit making and breaking means at the stations otl said telephone lilies for operating thc selecting mechanism at the exchange; and appie ratas brought into cooperative relation with the trunk line by the stations initially becoming connected therewith for locking out the selecting mechanism ope at-ingl means ot' the other station or stations seeking the trunk line.

9. A telephone exchange system including a'plurality of telephone lines; a telephone exchange; a trunk line leading to said telephone exchange from the stations of said telephone lines; selecting mechanism atthe exchange for automatically connecting extensions wit-h said trunk lines; means whereby either of the telephone lines may become connected with the trunk line; meansv at the stations of said telephone lines for operating the selecting mechanism at the exchange; and apparatus broughtl into cooperative relation with the trunk line by the station initially becoming connected therewith forV locking out other stations seeking connection with the trunk line during the time, that the selecting mechanism operating means of the stations tirst associated with the line is being operated.

L10. A telephone exchange system including a. plurality of telephone lines; a telephone exchange; a trunk line leading to said telephone exchange trom Athe stations ot' said telephone lines; selecting mechanism at the exchange for automatically connecting extensions with said trunk lines; means whereby either of the. telephone lines may become connected with the trunk line; circuit.- making and breakingmeans at the stations of said telephone lines for operating the selecting mechanism at the exchange; and apparatus broughtinto cooperativev relation with the trunk line by the station initially becoming connected therewith for locking out other stations seeking connection with the trunk line. during the time that the selecting mechanism operating means ol' the stations tirst associated with the line is bcing operated.

1l. A telephone .system including two or more telephone lines cach extending from its own station to the station of the other line, there being means governed at the telephone stations whereby telephonie connection may be etl'ected between the stations: a telephone exchange; a plurality of trunk lines interyening between said telephone exchange and the telephone stations ot the aforesaid lines; selecting mechanism at the exchange for automatically connecting extensions with said trunk lines; means interchangeably associated with the trunk lines for preventing the `selecting mechanism from separating a trunk line and the extension connected therewith by the selecting mechanism; and means `for preventing other telephone stations from effecting operative connection with a trunk line with which the aforesaid means has become operatively associated.

12. A telephone system including two or .more telephone lines each extending from its own station to the station of the other line; there being means governed at the telephone stations whereby telephonic connection may be effected between the stations; a telephone exchange; a plurality ot' trunk lines intervening between said telephone. exchange and the telephone stations of thc aforesaid lines: selecting mechanism at the exchange tor automatically connecting cxtensions with said trunk lines; electro-magnetic means interclningeably associated with the trunk lines t'or preventing the selecting mechanism from separating a trunk line and the extension connected therewith by the selecting mechanism; and means tor preventing other telephone stations t'rom eti'ecting ope ative connection with a trunk line with which the aforesaid means has become operatively associated.

In witness whereot'; l hereunto subscribe my inline this twenty third day of March;

ELMER R. CORWIN. fitnesses G. L. CRAGG, E'r'rA L. l/Vurrn.-

llt) 

